Earth Systems: Evolve Processes and 3

PART © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION EarthNOT FOR Systems: SALE OR DISTRIBUTION I Their Nature © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR andSALE OR DISTRIBUTION Their StudyNOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Part I of Earth’s Evolving Systems examines the principles and con- NOT FOR SALEChapter OR DISTRIBUTION 1 NOT FOR SALE OR DISTRIBUTION introduction: cepts critical to the study of the processes of each of the basic Earth investigating earth’s systems: the solid Earth, the hydrosphere, the atmosphere, and systems the biosphere. In examining these systems, Part I emphasizes the following: Chapter 2© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC plate tectonics NOT FOR SALE1. Why OR study DISTRIBUTION Earth history? NOT FOR SALE OR DISTRIBUTION Chapter 3 2. Basic components and behavior of each system and how they earth systems: evolve processes and 3. How changes in the distributions of the continents and oceans interactions© Jones & Bartlett Learning,a LLC ect the other systems © Jones & Bartlett Learning, LLC ChapterNOT FOR SALE 4 OR DISTRIBUTION4. How the interactions of Earth’sNOT systems FOR regulate SALE climate OR DISTRIBUTION sedimentary rocks, 5. The importance of geologic time to the study of physical and bio- sedimentary logical processes environments, 6. How we study Earth’s systems and Fossils © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALEChapter OR DISTRIBUTION 5 NOT FOR SALE OR DISTRIBUTION evolution and extinction Chapter 6 geologic time and© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC stratigraphy NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

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9781284457162_CH01_001_022.indd 2 07/11/16 10:44 am CHAPTER © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 1 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC introduction:NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION investigating earth’s © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC systemsNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Major Concepts and Questions Addressed in This Chapter © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION a Why study the history of Earth? e Why is geologic time important to understanding how B How did the science of Earth systems arise? Earth’s systems interact? C What is a system, and how does it work? F How do diff erent processes act on diff erent durations of time? d What are Earth’s systems, and what are their basic characteristics? © Jones & Bartlett Learning, LLCg How do we study Earth’s ©systems Jones and & the Bartlett history of Learning, LLC NOT FOR SALE OR DISTRIBUTIONtheir interactions? NOT FOR SALE OR DISTRIBUTION

Chapter© Jones & Bartlett Outline Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 1.1 Why study the history of earth? 1.4 directionality and the evolution of earth 1.2 What are the Major earth systems, and What systems are their Characteristics? 1.5 geology as an historical science © Jones & BoX Bartlett 1.1 TheLearning, Origins of theLLC Science of Earth Systems © Jones 1.6 & Method Bartlett and Learning, study of earth’s LLC evolving systems NOT FOR 1.3 SALE geologic OR DISTRIBUTION time and process NOT FOR SALE OR DISTRIBUTION

The Anasazi© cli Jones dwellings at Mesa& VerdeBartlett National Park, Learning,Colorado. The Anasazi (the LLC “Ancient Ones”) civilization vanished suddenly, possibly© asJones a result of prolonged & Bartlett drought. The Anasazi Learning, civilization once encompassed LLC an area the sizeNOT of New EnglandFOR in the SALE Four Corners regionOR where DISTRIBUTION Colorado, Utah, New Mexico, and Arizona meet today. Based on archeologicalNOT evidence, FOR the Anasazi SALE civilization ORourished DISTRIBUTIONduring what is called the Little Climate Optimum from about 900–1300, and traded with other civilizations as far south as Mexico and Central America. The Anasazi adopted an agricultural lifestyle and built extensive cities in the sides of cli s. However, the Anasazi began to disperse from about 1280–1300, leaving behind their dwellings, and their civilization disappeared. Similarly, increasing evidence indicates that modern global change—due to the combustion of fossil fuels—will alter precipitation patterns, leading to more intense heat waves and prolonged drought in di erent regions all over the world, including North America. Courtesy of National Park Service. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

9781284457162_CH01_001_022.indd 3 07/11/16 10:44 am the present (refer to this chapter’s frontispiece). Humans 1.1 Why study the history have now begun to affect Earth’s environments at rates much © Jones of& Bartlett earth? Learning, LLC © Jonesfaster &than Bartlett the rates Learning,of natural processes. LLC The rapid growth NOT FOR SALE OR DISTRIBUTION NOT ofFOR human SALE populations OR DISTRIBUTION ( Figure 1.1) has led to the spread of Earth’s Evolving Systems is about the history of the agriculture and deforestation, heavy industry and power a Earth, the natural processes that have shaped it, and plants fired by fossil fuels, and the dependence on petro- the history of these processes and their interactions through leum (oil and gas) to power automobiles for transportation vast intervals of time. Geology is the science that studies the (Figure 1.2). history of the Earth and© its Jones life preserved & Bartlett as fossils. Learning, LLCThe burning of fossil fuels© releasesJones greenhouse & Bartlett gases Learning,, LLC Why should we beNOT concerned FOR SALEabout Earth’s OR DISTRIBUTIONhistory? especially carbon dioxide, intoNOT the atmosphere. FOR SALE Greenhouse OR DISTRIBUTION Because understanding how the Earth changes and has gas traps solar radiation as heat in Earth’s atmosphere, caus- changed tells us about how natural processes affect humans ing the atmosphere and surface to warm (Figure 1.3). With- and how humans affect natural processes. The history of the out carbon dioxide in the atmosphere, Earth’s average surface Earth confronts us with events and possibilities that we can- temperature would be about –18°C (0.5°F) instead of its cur- not imagine.© Jones Many & natural Bartlett processes Learning, act so slowly LLC we would rent (and more© Jones comfortable!) & Bartlett temperature Learning, of +15°C LLC(59°F). be unawareNOT ofFOR them SALE except ORfor the DISTRIBUTION geologic record of their But humansNOT have FORbegun toSALE burn fossilOR DISTRIBUTIONfuels at an unprece- activities preserved by rocks and fossils. Most people are dented rate, and no one really knows what the outcome unaware that Earth’s environments are constantly changing. will be of the rapid accumulation of carbon dioxide in the We assume that landscapes—mountains, valleys, rivers and atmosphere. In fact, carbon dioxide levels in the atmosphere streams, and coasts—do not change because the changes are have increased about 30% since the beginning of the Indus- © Jones &typically Bartlett so slow Learning, and subtle theyLLC take place over time spans© Jonestrial Revolution & Bartlett ( Figure Learning, 1.4 ). We know LLC this based on carbon NOT FORequivalent SALE ORto many, DISTRIBUTION many human generations; from manyNOT concentrationsFOR SALE in OR gas DISTRIBUTIONbubbles found in core samples taken millions of years down to millennia and centuries. Also, some through the glacial ice of Greenland and Antarctica. The bub- processes are so infrequent or sudden, we would not know bles are a record of the composition of ancient atmospheres. they occur except, again, to look at the geologic record. As the use of fossil fuels has increased, so too has Earth’s aver- Scientists have only recently begun to appreciate just age surface temperature, so that the greenhouse effect is no B how strongly changes© Jones in Earth’s & Bartlett environments Learning, have LLClonger considered by most scientists© Jones to be &purely Bartlett natural. Learning, As LLC affected—and still affect—humankind,NOT FOR SALE from our OR evolution- DISTRIBUTIONfar as scientists can tell, these NOTchanges FOR will continueSALE throughOR DISTRIBUTION ary beginnings through the origins of ancient settlements the 21st century and beyond, potentially affecting future and civilizations—and perhaps their collapse—right up to human generations, environments, and ecosystems.

©8 Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 7

6 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE5 OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Green Revolution World War II 4 Advances in medicine/sanitation Railroads and steamships © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC 3

Population (billions) Industrial Revolution NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Emigration to New World begins 2 Black Death—the plague Rome Rise of Crusades begin Neolithic agricultural revolution falls Islam ©1 Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 0 8000 B.C. 1 A.D. 500 1000 1500 2016 Year Data from: United States Census Bureau, International Programs Center, 2001.

© Jones & Figure Bartlett 1.1 Human Learning, population LLC growth. Global human population© growth Jones since & 8,000 Bartlett B.C. Note Learning, the steep rise ofLLC population growth NOT FORbeginning SALE in OR the 1800sDISTRIBUTION in response to the Industrial Revolution andNOT advances FOR in medicine SALE and OR sanitation. DISTRIBUTION

4 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 4 07/11/16 10:44 am History 2016 Projections Figure 1.2 Historical and projected trends of world 250 energy consumption. Given the projection, society might © Jones & Bartlett Learning, LLC © Jones become& Bartlett increasingly Learning, dependent LLC on fossil fuels unless other energy sources are found. NOT FOR200 SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

150

100 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 50

0 1990 2000 2016 2020 2030 2040 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FORLiquid SALE fuels OR DISTRIBUTIONRenewables NOT FOR SALE OR DISTRIBUTION Coal Renewables with CPP Coal with CPP Nuclear Natural gas

© Jones &Data Bartlett from: the United States Learning, Department of Energy, Energy InformationLLC Administration, International Energy Annual, 2002, 2003© (May–July Jones 2005), & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION2005, and System for the Analysis of Global Energy Markets,NOT 2005 and 2006.FOR SALE OR DISTRIBUTION

(a) © Studio 1a Photography/Shutterstock, Inc.

Total reflected 3%

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC CO Methane 2 Water vapor NOT FOR SALE21% OR DISTRIBUTION NOT FOR SALE OR CHDISTRIBUTION4 Reflected 1–2% Absorbed from clouds 5% NO2 by plants Reflected Heat 67% Heat from dust Heat Heat © Jones & Bartlett Learning, LLC Heat© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

6% Reflected from Absorbed by air, water, soil, air, land, and water and vegetation converted to heat © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC (b) (c) NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Figure 1.3 (a) How a greenhouse works. Solar energy penetrates through the glass and is reflected by the floor of the greenhouse as infrared radiation. The infrared radiation is trapped by the glass ceiling and warms the interior of the greenhouse. (b) The atmospheric greenhouse effect works in the same way; atmospheric carbon dioxide acts like the glass ceiling of the greenhouse by trapping solar energy

that has been reflected by (c) the Earth’s surface as infrared radiation; this warms the atmosphere. Other gases like methane (CH4) can combine with oxygen to produce carbon dioxide (CO ) and greatly exacerbate global warming. Water vapor also contributes to warming. © Jones & Bartlett Learning, LLC 2 © Jones & Bartlett Learning, LLC But, scientists have focused on carbon dioxide because of the rapid increase of carbon dioxide concentrations in Earth’s atmosphere during NOT FORthe SALE past half OR century. DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

1.1 Why Study the History of Earth? 5

9781284457162_CH01_001_022.indd 5 07/11/16 10:44 am 5 9 8 © Jones & Bartlett4 Learning, LLC © Jones & BartlettIPCC prediction: Learning, LLC 7 2.7C, with band NOT FOR SALE OR DISTRIBUTION 6 NOT FOR SALE OR3 DISTRIBUTIONMesopotamia of uncertainty ﬂourishes 5 4 2 Agriculture Vikings in 3 Temperature Change (F) established Greenland ? 1 2 © Jones & Bartlett Learning, LLC © Jones & Bartlett 1 Learning, LLC 0 NOT FOR SALE OR DISTRIBUTION NOT FOR SALE 0 OR DISTRIBUTION 1940 –1970 – 1 – 1 – 2 “Little Ice Age” End of last in Europe – 3 – 2 ice age © Jones Change (C) Temperature & Bartlett Learning, LLC © Jones & Bartlett Learning,– 4 LLC – 5 NOT– FOR3 SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Average temperature over past 10,000 years 14°C (57.2°F) – 6

– 4 – 7 – 8 – 5 – 9 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC – 10 NOT FOR SALE OR DISTRIBUTION20,000 10,000 2000 1000NOT FOR200 SALE OR100 DISTRIBUTIONNow 100 18,000 years 1800 years 300 years

(a) Number of Years Before Present (note: quasi-log scale) Data from: McMichael, A. J. 1993. Planetary Overload. Cambridge, UK: Cambridge University Press. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT390 FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

380

370 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR360 DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

350

340 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION330 NOT FOR SALE OR DISTRIBUTION Carbon dioxide concentration (ppmv) dioxide Carbon 320

310 © Jones & 1960Bartlett Learning,1970 1980LLC 1990 2000 © Jones & Bartlett Learning, LLC NOT(b) FOR SALE OR DISTRIBUTIONYear NOT FOR SALE OR DISTRIBUTION Data from: Rhode, R. A. Atmospheric carbon dioxide, Global Warming Art , October 1, 2008.

Figure 1.4 (a) Earth’s average surface temperature increased during the last half century as compared to the previous 20,000 years. Note that some civilizations or settlements flourished during times of very mildly increased temperatures that were much lower than those of the past half century and projected into the future. There were also far smaller human populations during earlier times. (Compare Figure© 1.1.) Jones (b) Since & carbon Bartlett dioxide Learning, concentrations LLC in the Earth’s atmosphere began ©to beJones measured & in Bartlett 1958, atmospheric Learning, carbon dioxideLLC has risenNOT steadily. FOR These SALE measurements OR DISTRIBUTION were taken at a station at Mauna Loa, Hawaii.NOT Another FOR station SALE takes measurements OR DISTRIBUTION in Antarctica. The oscillations reflect seasonal changes in photosynthesis.

6 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 6 07/11/16 10:44 am The fact that Earth’s environment has likely affected 1.2 What are the Major earth C past civilizations and that anthropogenic —or © Jones human-generated—activities& Bartlett Learning, LLCsuch as fossil fuel combustion© Jonessystems, & Bartlett and Learning, What LLC are their NOT FORare SALE thought OR by almostDISTRIBUTION all scientists to be affecting Earth hasNOT FOR SALE OR DISTRIBUTION led to the study of Earth as a series of systems. A system can Characteristics? be viewed as a series of parts or components that interact Earth’s surface environments are regulated by four together to produce a larger, more complex whole. d major systems and their component subsystems Geology, then, is not just about describing and naming rocks (Figure 1.5). The solid Earth system consists of the nonliv- and fossils. The entire Earth© Jonescan be viewed & Bartlett as a system, Learning, and it is LLCing, solid Earth, from its center© Jonesto its surface, & Bartlett including Learning, the LLC the record of the interactionsNOT of its FOR component SALE systems OR that DISTRIBUTION we will continents and the seafloor. TheNOT atmosphere FOR SALE comprises OR theDISTRIBUTION study in this book. Geology is the science that examines the gaseous envelope surrounding Earth, whereas the hydro- evolution of the natural processes on Earth, the evolution sphere consists of the oceans, rivers and streams, lakes, and of life, and the evolution of these interactions and how they ice contained in mountain glaciers and polar ice caps. Gla- have caused Earth to evolve toward its present state. It is the ciers and related environments are sometimes grouped into geologic© Jonesrecord of &rocks Bartlett and fossils Learning, that preserves LLC the history a separate ©system Jones called & theBartlett cryosphere Learning, . The biosphere LLC of theseNOT interactions. FOR SALE This is ORwhat DISTRIBUTION geology studies. Humans consists of allNOT living FOR organisms SALE and OR their DISTRIBUTION dead remains. are now the primary geologic force on our planet because In this chapter, we consider the traits systems share in of the rapidity of anthropogenic change. It is the science common. First, each major Earth system consists of a series of Geology that provides the clues as to how the Earth and of parts or components that comprise a larger integrated and its life have behaved—often unpredictably from a modern, complex whole. Each of these components in turn consists © Jones &anthropogenic Bartlett Learning, view. LLC © Jonesof smaller & Bartlett parts with Learning, their own LLCsystems. Some compart- NOT FOR SALE What ORare these DISTRIBUTION systems and how do they interact? OverNOT mentsFOR maySALE serve OR as reservoirs DISTRIBUTION , in which certain types of what scales of time do these systems and their processes matter (e.g., carbon from photosynthesis) can be stored—or interact? What methods do we use to study the history of sequestered—for some length of time ranging from perhaps these systems, and how do we determine the durations of days or weeks to tens of millions of years or more. Second, time over which these systems interact? It is these questions most natural systems, both living and nonliving, are open © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC to which we devote the rest of this chapter. systems (Figure 1.6 ). This means that the reservoirs of the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Atmosphere (3.8 bya) © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Degassing

Hydrosphere (3.8 bya) © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Gases released NOT FOR SALE OR DISTRIBUTIONLithosphere NOT FOR SALE OR DISTRIBUTION (4.0 bya) Convection current

© Jones Figure& Bartlett 1.5 The Learning, four major systems LLC of the Earth and the basic processes© Jones within & each. Bartlett Note that Learning, each system has LLC its own components and NOT FORthat SALE each system OR isDISTRIBUTION cyclic. The approximate ages of the systems areNOT shown FOR as billions SALE of years OR ago DISTRIBUTION (bya).

1.2 What Are the Major Earth Systems, and What Are Their Characteristics? 7

9781284457162_CH01_001_022.indd 7 07/11/16 10:44 am © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE BoX OR 1.1 DISTRIBUTION the origins of the science ofNOT earth FOR systems SALE OR * DISTRIBUTION

Like so many other scientific disciplines, the science chemist Louis Pasteur, one of the founders of of Earth systems originated through the work of more medical microbiology, and the French physiologist than one person. But© ifJones its origins & canBartlett be traced Learning, to LLCClaude Bernard on the concept© of Jones homeostasis & Bartlett (the Learning, LLC one person in particular,NOT it FOR would SALE likely be OR the Russian DISTRIBUTION tendency of a system to maintainNOT its internalFOR SALE stability OR DISTRIBUTION scientist Vladimir Ivanovich Vernadsky (1863–1945), in response to external disturbances). Vernadsky also whose work and integrity are a source of national conducted experimental studies on minerals with the pride in both Russia and the Ukraine (BOX Figure French chemist Henri Louis Le Châtelier in Paris. 1.1A© Jones ). Vernadsky & Bartlett is so famous Learning, that he has LLChad streets Vernadsky’s © Jones The Biosphere & Bartlett , first published Learning, in LLC andNOT monuments FOR SALE erected OR in his DISTRIBUTION honor and his image Russian in 1926,NOT was FOR translated SALE into OR French DISTRIBUTION in 1930, reproduced on postage stamps. In perhaps his but, unfortunately, was not translated into English greatest work, The Biosphere , Vernadsky stated that until 1998; thus, many western scientists remained life is not only a geologic force, it is the geologic force, unaware of it until aft er the Second World War, when and that the role of life on the Earth has increased some of Vernadsky’s major themes were summarized © Jones & Bartlettthrough time. Learning, Indeed, humans LLC have become the © Jonesby the &ecologist Bartlett G. Evelyn Learning, Hutchinson LLC (1903–1991). NOT FOR SALEprime OR geologic DISTRIBUTION agent on Earth. NOTVernadsky’s FOR SALE work OR then DISTRIBUTION began to give rise to various But Vernadsky also had very broad, interdisciplinary fields such as geomicrobiology and biogeochemistry: interests, stimulated by the work of the French the study of geologically and biologically important chemical cycles like those discussed in this text. © Jones & Bartlett Learning, LLC Similar themes began to be© advocatedJones & in Bartlett the Learning, LLC West during the 1970s by the British scientist James NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Lovelock in his Gaia hypothesis (named aft er the Greek goddess of mother Earth), which advocated a “physiology” of the Earth involving not only life but also temperature, atmospheric composition, © Jones & Bartlett Learning, LLC and ocean chemistry.© Jones Nevertheless, & Bartlett many Learning, western LLC NOT FOR SALE OR DISTRIBUTION scientists, includingNOT FOR Lovelock, SALE remained OR DISTRIBUTIONunaware of Vernadsky’s work until aft er the Gaia hypothesis had been developed. As we will see, although Lovelock’s hypothesis advocated homeostasis, the Earth’s systems have also undergone profound directional © Jones & Bartlett Learning, LLC © Joneschange, & or Bartlett evolution. Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION *Summarized from Margulis, L. Foreward, and Grinevald, J. 1998. Introduction: The Invisibility of the Vernadskian Revolution, in Vernadsky, V. I. The Biosphere. Copernicus/Springer-Verlag. New York, NY. (Translated by D. B. Langmuir; M. A. McMenamin, Editor), © RIA Novosti/Science Source. © Jones & Bartlett Learning, LLCpp. 14–32. © Jones & Bartlett Learning, LLC BoX Figure 1.1a Vladimir Ivanovich Vernadsky. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

systems exchange matter (chemical substances) and energy (space) as the molten material cools to form solid rock to (like sunlight) with their surrounding environment. It is produce the ocean floor and continents of Earth’s outer shell, the flow© Jones of matter & andBartlett energy Learning,through systems LLC and their or crust. © Jones & Bartlett Learning, LLC exchangeNOT of FORmatter SALE and energy OR with DISTRIBUTION other systems and the Convection NOT cells FOR and SALE seafloor ORspreading DISTRIBUTION are also respon- surrounding environment—termed fluxes—that keeps sible for the movement of the continents and large pieces open systems functioning. For example, convection cells of the lithosphere (the crust and uppermost mantle of the (like those found in a pot of boiling water) transfer heat and solid Earth), called plates, in what is known as plate tec- molten rock from deep within the Earth toward its surface tonics . Plate tectonics (or tectonism) refers to the processes © Jones &during Bartlett the process Learning, of seafloor LLC spreading. The heat is radi-© Jonesthat cause & Bartlett the movement Learning, of these LLC plates. These processes NOT FORated SALE from Earth’sOR DISTRIBUTION surface into the surrounding environmentNOT haveFOR produced SALE mountainOR DISTRIBUTION chains, ocean basins, and other

8 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 8 07/11/16 10:44 am Venus Earth (no life) Vapor System System 0.1% © Jones & Bartlett Learning, LLC © Jones3.5% & Bartlett Learning, LLC1. 9% NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Heat Heat

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION (a) Open system (b) Closed system (c) Isolated system 96.5% 98% (a,b,c) Data from: Coveney, P., and Highfi eld, R. 1991. The Arrow of Time: A Voyage through Science to Solve Time’s Greatest Mystery. New York: Fawcett Columbine.

Figure 1.6 (a) An open system exchanges both matter and energy© with Jones its surroundings. & Bartlett (b) A closedLearning, system exchanges LLC Surface temperature© Jones °C (459) & BartlettSurface Learning, temperature °C (240LLC to 340) Total pressure, bars (90) Total pressure, bars (60) energyNOT (by temperature FOR SALE changes) OR with DISTRIBUTION its surroundings. (c) An NOT FOR SALE OR DISTRIBUTION isolated system does not exchange matter and energy with its surroundings. Natural systems are typically open systems. Mars Modern Earth (with life) 1. 6% 0.13 1.7 ppm 0.03% 2.7% 1.0% © Jones &features Bartlett on Earth’s Learning, surface, all LLC the while interacting with the© Jones & Bartlett Learning, LLC NOT FORother SALE Earth OR systems, DISTRIBUTION which have profoundly affected Earth’sNOT FOR SALE OR DISTRIBUTION climate through geologic time. 21% Convection cells also occur within Earth’s atmosphere. Atmospheric convection cells result from the differential heating of Earth’s surface and distribute heat and moisture over Earth’s surface, thereby© Jones affecting & Bartlettsurface temperatures Learning, LLC © Jones & Bartlett Learning, LLC 95% 79% and the precipitation patternsNOT FORof the SALEhydrosphere. OR WaterDISTRIBUTION is NOT FOR SALE OR DISTRIBUTION critical to life as we know it on Earth; most organisms consist of more than 60% water (and some more than 90%). Water also provides habitats for organisms. Like carbon dioxide, water vapor also acts as a greenhouse gas, affecting Earth’s Surface temperature °C (–53) Surface temperature °C (13) Total pressure, bars (0.0064) Total pressure, bars (1.0) temperature© Jones and habitability.& Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The NOT energy FOR of SALEsunlight ORpenetrating DISTRIBUTION the atmosphere is NOT FOR SALE OR DISTRIBUTION also used by plants during photosynthesis to produce simple Carbon dioxide sugars from carbon dioxide and water. These plants are then Nitrogen Oxygen eaten by herbivores and their stored energy is in turn con- Argon sumed by predators higher in food pyramids. The biosphere Methane

© Jones &has Bartlett had a profound Learning, impact on LLC the evolution of the Earth. In© Jones & BartlettData from: Learning, Lovelock, J. 1988. The Ages of Gaia:LLC A Biography of Our Living Earth. New York: W. W. Norton. NOT FORfact, SALE life may OR be viewedDISTRIBUTION as a geologic force. Without the evolu-NOT FOR SALE OR DISTRIBUTION tion of photosynthesis on Earth and the storage of carbon Figure 1.7 The carbon dioxide concentration of the Earth’s atmosphere as compared to that of Mars and Venus if life had not dioxide in plant matter, the carbon dioxide levels of Earth’s evolved on Earth. atmosphere would more nearly resemble those of Mars or Venus and there would be little or no oxygen present for respiration ( Figure 1.7©). PlantsJones also & profoundlyBartlett Learning,affect the LLCsent to the amplifier, which enhances© Jones the signal& Bartlett and sends Learning, it LLC physical and chemical breakdown—orNOT FOR SALE weathering OR —of DISTRIBUTION the to a speaker. The speaker thenNOT converts FOR the amplifiedSALE OR electri- DISTRIBUTION rocks of Earth’s crust. Weathering processes are critical to cal signals back into vibrations (sound), which are picked up the long-term, or geologic, cycle of carbon that occurs over by the microphone and sent to the amplifier, producing an tens of millions of years, as we will see in coming chapters. ear-piercing sound. Negative feedback in this system would These examples illustrate another important point have just the opposite effect: the reduction of sound. e ©about Jones Earth’s & systems, Bartlett namely Learning, that they interact LLC to reg- Typically,© Joneshowever, & positive Bartlett and Learning,negative feedback LLC act ulate NOTEarth’s FOR climate SALE and maintain OR DISTRIBUTION it in a relatively stable together to NOTmaintain FOR homeostasis SALE withinOR DISTRIBUTION a system; otherwise, state (homeostasis). These interactions occur through feed- the system would spiral out of control (positive feedback) back (Figure 1.8). Positive feedback promotes an effect, or go to extinction (negative feedback). Another example of whereas negative feedback counters an effect. Most of us are homeostasis produced by feedback is the temperature con- all too familiar with one type of positive feedback: audio trol of a house. If the house becomes too cold, a thermostat © Jones &feedback. Bartlett In Learning,a sound system, LLC the microphone converts© Jonesis triggered & Bartlett that turns Learning, on the furnace LLC to warm the house to NOT FORsound SALE (vibrations OR DISTRIBUTION in the air) into electrical impulses that areNOT theFOR desired SALE level ORset on DISTRIBUTION the thermostat. If the house becomes

1.2 What Are the Major Earth Systems, and What Are Their Characteristics? 9

9781284457162_CH01_001_022.indd 9 07/11/16 10:44 am Positive feedback 1.3 geologic time and process A © Jones & Bartlett Learning, LLCOpen B © Jones Our & Bartlett discussion Learning, of feedback has LLC raised the related issues + system NOT FOR SALE OR DISTRIBUTION NOT FORF of SALEtime and OR process. DISTRIBUTION The processes relevant to the study of Earth’s systems vary according to the duration of time involved. Many processes occur so slowly they are imperceptible to us on human time scales. Nevertheless, these processes have Negative feedback had a profound impact on Earth’s environments over long © Jones & Bartlett Learning, LLCspans of many millions of years.© Jones On the &other Bartlett hand, some Learning, LLC NOTA FOROpen SALEB OR DISTRIBUTIONprocesses are so rare, we wouldNOT not knowFOR they SALE occur OR except, DISTRIBUTION – system again, to look at the geologic record. In either case, though, the only way to detect the existence of these processes, their potential impact on humanity, and humanity’s potential impact on them is to examine the geologic record of these changes as they are Figure© 1.8Jones Positive & and Bartlett negative feedbackLearning, are involved LLC in preserved by© the Jones rocks and & fossils. Bartlett Learning, LLC temperatureNOT regulation.FOR SALE OR DISTRIBUTION To comeNOT to grips FOR with SALE this important OR DISTRIBUTION realization, one must wrestle with the enormity of geologic time. As the first too hot, the thermostat is triggered to lower the temperature. Earth scientists began to study the planet’s history in earnest, Both positive and negative feedback must act together to they quickly recognized that rocks occur in layers that lay counterbalance each other; otherwise, a system would shift on top of one another. In the 1600s this basic observation © Jones &too Bartlett far in one direction.Learning, LLC © Jonesby Nicolaus & Bartlett Steno ledLearning, to the Principle LLC of Superposition, NOT FOR SALE The regulation OR DISTRIBUTION of atmospheric carbon dioxide and otherNOT whichFOR states SALE that OR in a sequenceDISTRIBUTION of rocks, younger rocks lie on greenhouse gases has acted in a similar manner ( ). Figure 1.9 top of older rocks ( Figure 1.10). Thus, the sequence of rocks Nevertheless, Earth systems may act in a nonlinear manner, provides what are called relative ages , meaning that some- meaning that the effect is much greater than the cause. thing is older or younger than something else. Still, most scientists refrained from speculating on how old the rocks were © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ConCept and reasoning CheCks and generally assumed the Earth was only a few thousand NOT FOR SALE OR DISTRIBUTIONyears old, based on biblical interpretation.NOT FOR SALEDuring the OR 18th DISTRIBUTION and early 19th centuries, however, scientists began to realize 1. What are the characteristics of open systems? that Earth was far older than previously imagined. One of 2. Are natural systems open systems? 3. What are the basic components of each system just the primary pieces of evidence for this conclusion was the described? relationship of stratified rocks like those at Siccar Point, along © Jones & Bartlett Learning, LLC the northeast© Jonescoast of England.& Bartlett Here, Learning, horizontally LLClayered NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Atmosphere

CO Diffusion © Jones & Bartlett Learning, LLC 2 © Jones & Bartlett Learning, LLC Volcanic NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTIONactivity Photosynthesis

Burning Plant biomass © Jones & Bartlett Learning,plants LLC © Jones & Bartlett Learning, LLC stores CO2 Burning NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION food Respiration

Decomposition © Jones & Bartlett Learning, LLC © COJones2 dissolves & Bartlettin ocean Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Fossil fuel

© Jones & Figure Bartlett 1.9 The Learning, carbon cycle. LLCPhotosynthesis, respiration, and organic© Jones decay in& the Bartlett carbon cycle Learning, transfer matter LLC and energy between NOT FORreservoirs SALE within OR ecosystems.DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

10 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 10 07/11/16 10:44 am 1815 of the Principle of Faunal Succession, which states that different groups of fossils follow each other in a char- © Jones & Bartlett Learning, LLC © Jonesacteristic & Bartlett upward sequence, Learning, that LLCis, through time. Faunal NOT FOR SALE OR DISTRIBUTION NOT successionFOR SALE was originallyOR DISTRIBUTION established in England, but with its recognition scientists began to look more closely at the occurrence of fossil assemblages elsewhere. This led to the development of the geologic time scale, the subdivisions of which are largely based on the occurrence of distinctive fos- © Jones & Bartlett Learning, LLCsil assemblages through time© ( FigureJones 1.13 & ).Bartlett For example, Learning, LLC NOT FOR SALE OR DISTRIBUTIONthe Cretaceous Period, when NOTEarth wasFOR quite SALE warm ORand theDISTRIBUTION seas quite high, is named for the widespread chalks (“creta”) that consist of the microscopic remains of ancient plankton Courtesy of Ronald Martin, University of Delaware. that floated in the seas during this period and which are integral to the geologic cycle of carbon that occurs on durations Figure 1.10 The Principle of Superposition states that younger rocks are© Joneslaid down &on topBartlett of older rocks.Learning, Thus, the oldestLLC rocks of many millions© Jones of years & (BartlettFigure 1.14 Learning,). The geologic LLC time occur NOTat the bottom FOR of SALE the section OR and DISTRIBUTION the youngest at the top. scale is, then,NOT a record FOR of SALEthe history OR of DISTRIBUTION life itself. What the These stratified (layered) rocks are exposed in the Grand Canyon. overall succession of life forms tells us is that life on Earth evolved during a time span of 4.5 to 5 billion years from the relatively simple to the, seemingly, more “advanced.” (or stratified [from “stratum” for layer]) rocks had origi- Because the biosphere has interacted with and influenced © Jones &nally Bartlett been laid Learning, down and then LLC tilted and eroded, after which© Jonesthe other & Bartlett Earth systems Learning, through thisLLC span, it is paramount NOT FORmore SALE stratified OR rocksDISTRIBUTION were deposited on top (Figure 1.11).NOT thatFOR the SALE student ORknows DISTRIBUTION the geologic scale of time and how it Because processes that could produce such phenomena are evolved (Figure 1.13; see also Chapter 6). not observed, the inference was that the processes must occur The initial time scale represented relative ages. Much that produced the rocks themselves and their angular rela- later, during the 20th century, absolute ages (dates in years) tionship must occur unimaginably slowly as compared to began to be determined from the rates of radioactive decay human time scales. The ©recognition Jones of& the Bartlett enormity Learning, of time is LLCof certain minerals. Because ©radioactive Jones elements& Bartlett decay Learning, at LLC generally attributed to theNOT so-called FOR father SALE of geology, OR DISTRIBUTION James known rates, they can be usedNOT to calculate FOR SALE the ages OR of theDISTRIBUTION Hutton (1726–1797), a Scottish farmer who was a member rocks in which they occur. The modern time scale, which of a small circle of Enlightenment naturalists and scientists incorporates both changes in fossil assemblages through time of the 1700s who periodically met in the pubs of Edinburgh, and absolute ages, is routinely used in studies of Earth sys- Scotland, to discuss natural history and science (or “natural tems, and we will refer to it frequently throughout this book. philosophy,”© Jones as it was& Bartlett called in those Learning, days) (Figure LLC 1.12). The initial© Jones recognition & Bartlett that Earth Learning, was quite old LLC raised AboutNOT this FOR time, SALE fossils wereOR alsoDISTRIBUTION coming to be accepted several profoundNOT scientificFOR SALE and philosophical OR DISTRIBUTION questions: Are as evidence for prehistoric life. The presence of fossils as the processes that we observe and measure today on human evidence of ancient life eventually led to the recognition in time scales necessarily representative of the geologic past? In

(a) Courtesy of Clifford E. Ford. (b) © Jones &Figure Bartlett 1.11 (a)Learning, James Hutton LLC recognized the enormity of geologic© Jones time based & on Bartlett his observations Learning, of soil formation LLC and the NOT FORrelationships SALE OR of stratified DISTRIBUTION rocks like those at Siccar Point, Scotland.NOT (b) Interpretation FOR SALE of the ORevents DISTRIBUTION affecting the relations of the strata.

1.3 Geologic Time and Process 11

9781284457162_CH01_001_022.indd 11 07/11/16 10:44 am © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

(a) Courtesy of National Library of Medicine. (b) Courtesy of National Library of Medicine. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FORFigure SALE 1.12 OR Two DISTRIBUTION founders of geology. (a) James Hutton (1726–1797).NOT (b) FOR Sir Charles SALE Lyell OR (1797–1875), DISTRIBUTION who is credited with formulating the Principle of Uniformitarianism.

LithosphereBiosphere Era Age Lithosphere Hydrosphere Atmosphere 0 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Sea level “Ice ages” NOT FORLow SALE OR DISTRIBUTIONGlobal NOT FOR SALE OR DISTRIBUTION temperature Flying Cenozoic Cool mammals Humans Swimming Flowering Advanced Continents mammals seed plants High insects Mass separating Mammals Birds 65 extinction© Jones & Bartlett Learning, LLC Warm © Jones & Bartlett Learning, LLC my Swimming Reptiles NOT FOR SALE OR DISTRIBUTION reptiles NOT FOR SALE OR DISTRIBUTION Mesozoic Continents separating Flying Primitive Mass Low Cool Seed plants reptiles birds extinction 245 my Pangaea Primitive © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLCinsects Warm NOT FOR SALE OR DISTRIBUTIONContinents NOT FOR SALE OR DISTRIBUTION Paleozoic Amphibians assembling High Fishes Seedless Abundant Invertebrates Algae plants fossils 542 my Larger, slower© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC plates Modern oxygen Multicellular life 1500 NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION my levels Sexual reproduction Small, rapid Complex cells Precambrian plates 3500 Plate tectonics Modern volume my and composition Origin of life © JonesCrust & Bartlett forms Learning, LLC © Jones & Bartlett Learning, LLC Ocean origin NOT4600 FOREarth SALE origin OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION my

Figure 1.13 The simplified geologic time scale and its basic subdivisions. Many of the subdivisions are based on the Principle of Faunal Succession, which recognizes that the Earth’s biota has changed through time. Some of the major changes in the biotas are shown. The absolute ages come from radioactive elements that decay at known rates. The eras and periods of the geologic time scale were largely © Jones &recognized Bartlett in the Learning, 19th century. “Paleozoic”LLC refers to “ancient life,” “Mesozoic”© Jones as &“middle Bartlett life,” when Learning, more modern LLC forms began to greatly NOT FORdiversify, SALE and OR “Cenozoic” DISTRIBUTION means “recent life,” many forms of whichNOT have persisted FOR SALEto the present. OR DISTRIBUTION

12 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 12 07/11/16 10:44 am other words, does nature act in a uniform manner? If so, it interested in how soils form and are replenished. Among his must take a long time for many geologic processes to have conclusions was that natural processes are self-renewing, or © Jones an& effect.Bartlett Or, can Learning, the rates of LLCthe processes vary, and can the© Jonescyclic, & like Bartlett the circulation Learning, of the blood LLC (and the processes of NOT FORprocesses SALE themselves OR DISTRIBUTION vary through time? NOT Earth’sFOR systemsSALE introducedOR DISTRIBUTION previously in this chapter). Hut- The guiding principle that leads Earth scientists through ton further concluded that these processes are typically quite the maze of Earth processes and systems is the Principle slow and so the Earth’s history must span an unimaginable of Uniformitarianism. This principle is frequently stated amount of what we now call “geologic time.” as “the present is the key to the past.” In other words, the He also became interested in how rocks form. Hutton processes we observe today© Jones are the &same Bartlett as those Learning,that have LLCwas well aware of the power of© heatJones because & ofBartlett other studies Learning, LLC always operated. The originsNOT ofFOR uniformitarianism SALE OR areDISTRIBUTION typi- of how to make steam enginesNOT more FOR efficient SALE for the OR ongo DISTRIBUTION- cally traced to James Hutton’s Theory of the Earth, with Proofs ing Industrial Revolution. He ultimately concluded that and Illustrations (1795), which discussed his observations mountain building results from the activity of heat and that and those of others. Some earlier scientists had begun to Earth therefore had to have an internal source of heat. In think along similar lines, even going so far as to believe Earth Hutton’s theory, volcanoes acted as valves to release the heat was quite© Jones old, but & Hutton Bartlett was theLearning, first to have LLC synthesized and pressure© generated Jones within& Bartlett the Earth Learning, (we now know LLC that his ideasNOT into FOR a theory SALE based OR on DISTRIBUTIONobservation. Hutton had the source ofNOT Earth’s FOR internal SALE heat isOR radioactive DISTRIBUTION decay, which been trained as a physician and, as a student, had defended drives the processes of plate tectonics). a thesis on the circulation of human blood. Hutton’s stud- Hutton’s work laid the foundation for more serious geo- ies in medicine undoubtedly influenced his view of Earth’s logic inquiry in the 19th and 20th centuries. Among these processes. After he inherited a small farm, Hutton became works, those of Sir Charles Lyell (1797–1875) have perhaps © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

(b) Courtesy of Michele Miller. Figure 1.14 (a) The skeleton of a modern unicellular alga called a coccolithophore. (b) The White Cliffs of Dover consist of chalk © Jones &produced Bartlett by vast Learning, numbers of these LLC kinds of algae during the geologic© Jones period called & Bartlett the Cretaceous Learning, (“creta” means LLC chalk) period, when the NOT FORseas SALE flooded OR the continentsDISTRIBUTION (refer to Figure 1.13). NOT FOR SALE OR DISTRIBUTION (continues)

1.3 Geologic Time and Process 13

9781284457162_CH01_001_022.indd 13 07/11/16 10:44 am Carbon cycle

CO2

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 0.5 5.5 121.3 Vegetation 60 60 610 Fossil fuels and 1.6 cement production © Jones & Bartlett Learning, LLC © Jones & Bartlett4000 Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Soils 1580 92 Rivers 90 Surface ocean 1020 © Jones & Bartlett Learning, LLC 50 © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Marine biota 40 3 91.6 100

6 4 Deep ocean Storage in GtC © Jones & Bartlett Learning, LLC 38.100 © Jones Fluxes& Bartlett in GtC/yr Learning, LLC Dissolved organic 6 NOT FORcarbon SALE <700 OR DISTRIBUTION0.2 NOT FOR SALE OR DISTRIBUTION

Sediments 150

(c) © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning,Courtesy of NASA Earth Science LLC Enterprise. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Figure 1.14 (Continued) (c) Coccolithophorids and other calcareous plankton are involved in the geologic cycle of carbon. Modern volcanoes pump carbon dioxide into the atmosphere; feedback by increasing levels of carbon dioxide in the atmosphere resulting from ancient eruptions must have similarly spewed enormous volumes of the same gas into the atmosphere. The carbon dioxide then remained in the atmosphere for long periods of time, spanning tens of millions of years. Based on the greenhouse effect, the carbon dioxide warmed the Earth, speeding up—through positive feedback—the chemical reactions involved in the weathering of rocks on land. As these reactions © Jones &were Bartlett speeded up, Learning, they in turn began LLC to act as negative feedback: much© Jones of the carbon & Bartlett dioxide pumped Learning, into the atmosphereLLC by volcanism NOT FORwas SALE used up OR by weathering, DISTRIBUTION eventually lowering atmospheric concentrationsNOT FOR of carbon SALE dioxide OR and DISTRIBUTION lowering Earth’s surface temperature. These weathering reactions produce a type of sedimentary rock called limestone. The carbon dioxide in the atmosphere is transferred to

and sequestered (or stored) in limestone by coccolithophorids that secrete microscopic platelets of calcium carbonate (CaCO3) to produce a form of limestone. In the geologic past these particular organisms produced vast amounts of limestone on the continents, but if the limestones are deposited in the deep sea, they can eventually be carried into deep-sea trenches, where they are subducted and heated. The carbon dioxide stored© in theJones limestone & Bartlett(as carbonate) Learning, is released and LLC vented back to the atmosphere ©through Jones volcanoes. & Bartlett These Learning, LLC processes therefore act as positive feedback on atmospheric carbon dioxide levels. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

had the greatest influence on geology (Figure 1.12). Lyell catastrophic changes such as earthquakes or volcanic erup- developed Hutton’s views further by gathering enormous tions occurred on a local basis, but he condemned the con- amounts of evidence from his travels in Europe. Lyell’s syn- cept of global catastrophes that he attributed to the so-called thesis© of Jones his observations & Bartlett and Learning,conclusions resulted LLC in the catastrophists.© Jones According & Bartlettto Lyell, catastrophismLearning, LLCviewed publicationNOT FORof his three-volumeSALE OR treatise,DISTRIBUTION titled Principles of the Earth’s NOTgeologic FOR record SALE as having OR resulted DISTRIBUTION from a series Geology, in England in 1830; 11 more editions of the Princi- of sudden global catastrophes. Lyell also argued that cata- ples followed into the 1870s. strophism was an attempt to make Earth’s age fit with a chro- Lyell is usually credited with developing the Principle nology (time scale) derived from the Bible. This portrayal of of Uniformitarianism (although he did not coin the term), catastrophism by Lyell was grossly inaccurate, but Lyell was © Jones &which Bartlett he used Learning, to counter LLCthe rival doctrine of what he© Jonesa lawyer & andBartlett he used Learning, his skills at argumentation LLC and rhetoric NOT FORderisively SALE ORcalled DISTRIBUTION catastrophism. Lyell did not deny thatNOT toFOR build SALE a convincing OR DISTRIBUTIONargument for his own case.

14 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 14 07/11/16 10:44 am According to Lyell, the Principle of Uniformitarian- ism meant that the natural processes of today have always © Jones remained& Bartlett the sameLearning, and are thereforeLLC typically very slow and© Jones & Bartlett Learning, LLC NOT FORgradual. SALE Indeed, OR DISTRIBUTION given that Earth is now known to beNOT FOR SALE OR DISTRIBUTION approximately 4.5 to 5 billion years old (based on absolute ages), there has been plenty of time for very slow processes to produce major changes on Earth, just as Lyell (and Hut- ton) said. Lyell also concluded, however, that not only are the rates of geologic processes© Jones typically & Bartlett slow and Learning, gradual, LLC © Jones & Bartlett Learning, LLC but the rates of modern NOTprocesses FOR are exactly SALE the ORsame DISTRIBUTION as those NOT FOR SALE OR DISTRIBUTION that have acted in the past. Lyell’s concept of slow, gradual change dominated geologic thought until well into the 20th century, and his influence on the earth sciences up to the Courtesy of Billy Glass, University of Delaware. present cannot be overestimated. Figure 1.15 The geologic record of a mass extinction. The The © Jonesuniformitarian & Bartlett approach Learning, is sometimes LLC referred to hammer spans© aJones dark layer & enriched Bartlett in the Learning, chemical element LLC as actualism NOT FOR . According SALE to OR actualism, DISTRIBUTION processes observed iridium preservedNOT in FORsedimentary SALE rocks OR in Colorado. DISTRIBUTION The iridium in modern environments, using modern analogs , or exam- layer formed about 65 million years ago at the end of the ples, can be extrapolated to the interpretation of ancient Cretaceous Period as a result of the collision of an extraterrestrial environments. Thus, if a past phenomenon can be explained body with the Earth. The collision sent enormous volumes of dust as a result of processes actually observed today, we need not and iridium into the atmosphere and then settled to produce a © Jones &invent Bartlett or search Learning, for other processes LLC to explain the phenom-© Jonesglobal &layer Bartlett marking the Learning, extinction. This LLC particular extinction is thought to have resulted in the final demise of the dinosaurs. NOT FORenon. SALE In this OR view DISTRIBUTION the Principle of Uniformitarianism is theNOT FOR SALE OR DISTRIBUTION broader assumption that the behavior of nature has been uniform through time. Geologists and paleontologists (those who study the history of life) are especially proud to claim duration of time, and (3) sometimes highly unusual conditions the Principle of Uniformitarianism as their own because of and phenomena occur, including catastrophic ones like meteor its implications for Earth© history.Jones Nonetheless, & Bartlett the Learning, Principle LLCimpacts and mass extinctions. © Jones & Bartlett Learning, LLC of Uniformitarianism underliesNOT FORall scientific SALE inquiry. OR NoDISTRIBUTION form NOT FOR SALE OR DISTRIBUTION of scientific research could be conducted if nature did not behave—and if we did not assume that nature behaves—in a 1.4 directionality and the relatively uniform manner. For example, chemical elements and the compounds they form must have always behaved evolution of earth systems the same© Jones way chemically; & Bartlett otherwise, Learning, a chemist LLC could not An important© Jonesaspect of &Lyell’s Bartlett Principles Learning, of Geology wasLLC that conductNOT meaningful FOR SALE research, OR even DISTRIBUTION under the controlled he did not NOTdiscuss FOR what heSALE called OR Earth’s DISTRIBUTION “cosmogony,” or conditions of a laboratory experiment. Normally, actual- origins; to do so, according to Lyell, exceeded the bounds ism and the Principle of Uniformitarianism seem to work of uniformitarianism. This is because Lyell envisioned quite well, as attested to by, say, obtaining similar results in Earth as being in equilibrium , meaning that a system repeated laboratory experiments. exhibits no net change. Thus, according to Lyell, Earth had © Jones & BartlettWhat is Learning,typically left unsaid LLC about uniformitarianism© Jonesundergone & Bartlett no net changeLearning, through LLC time. To be sure, Lyell g NOT FOR SALEand actualismOR DISTRIBUTION is that the past is often the key to the pres-NOT envisionedFOR SALE Earth OR as changing,DISTRIBUTION but he envisioned no over- ent. As we have already noted, the geologic record demon- all, or net, change to Earth. In Lyell’s view, for example, strates that there are processes acting on Earth that either act mountains forming in one place were counterbalanced by so slowly or so infrequently as to be imperceptible on human erosion somewhere else. time scales. Moreover, scientific reasoning from rocks and Although Earth’s systems do behave in a cyclic manner, fossils often indicates that,© Jonesgiven enough & Bartlett time, unusual Learning, pro- LLCas Lyell and Hutton envisioned,© thereJones is substantial & Bartlett evidence Learning, LLC cesses or events not observedNOT FORtoday haveSALE also OR occurred. DISTRIBUTION In that Earth has also evolved; thatNOT is, thatFOR the SALEseemingly OR equi- DISTRIBUTION fact, we now know that present-day conditions were often librium states of Earth (no net change) have actually shifted not representative of the past and that a number of unusual— through time in particular directions. This is because of the even catastrophic—changes on Earth have occurred. For flux—the inflow and outflow—of matter and energy through example, we know from the geologic record that movement the open systems and subsystems of the Earth ( Figure 1.6 ). of the© continents Jones &on Bartlett geologic scales Learning, of time hasLLC interacted Open systems© Jones are often &said Bartlett to be in “equilibrium” Learning, with LLC their with NOTthe other FOR Earth SALE systems OR to drastically DISTRIBUTION alter climate. The surroundingsNOT because FOR they SALE appear OR to be DISTRIBUTION undergoing no net geologic record also tells us that at times meteors have col- change. This is because we do not observe these systems lided with Earth to produce certain mass extinctions over sufficiently long durations of time, geologic time. Such (Figure 1.15). Thus, Earth scientists have broadened their open systems are more accurately said to be in steady state, view of the Principle of Uniformitarianism to mean that but even this term is a bit of a misnomer. Systems in steady © Jones &(1) Bartlett processes haveLearning, largely remained LLC the same but the rates of© Jonesstate actually& Bartlett exist farLearning, from the true LLC equilibrium of an iso- NOT FORthe SALE processes OR can DISTRIBUTION vary, (2) processes vary according to theNOT latedFOR system. SALE Tr uOR e equilibrium DISTRIBUTION is tantamount to the death

1.4 Directionality and the Evolution of Earth Systems 15

9781284457162_CH01_001_022.indd 15 07/11/16 10:44 am of a living organism; the exchange of matter and energy by the living organism with its environment has ceased. Open ConCept and reasoning CheCks 1.4 © Jones systems& Bartlett can undergo Learning, directional LLC change because the flux of© Jones & Bartlett Learning, LLC NOT FORmatter SALE and OR energy DISTRIBUTION maintains them far from this true equilib-NOT FOR1. What SALE distinguishes OR DISTRIBUTIONthe Principle of Uniformitarianism as rium. (You might want to consult von Bertalanffy’s book. For Lyell recognized it from the Principle of Uniformitarianism more details about it, go to the section “Sources and Further as it is now recognized? Reading.”) 2. What sorts of evidence indicate directionality in Earth’s Indeed, as indicated by the title of this book, Earth’s history? systems have evolved and© continueJones to & evolve. Bartlett The wordLearning, evo- LLC3. What has caused directional© change Jones in Earth’s & Bartlett history? Learning, LLC lution means to developNOT or unfold.FOR SALE In the caseOR ofDISTRIBUTION Earth NOT FOR SALE OR DISTRIBUTION as a whole, with all its interacting systems, the evolution of Earth has resulted in directionality —or secular change —through time. Thus, even though Earth’s systems act in a cyclic manner, they also tend to change, inexora- 1.5 geology as an historical bly, in© certain Jones directions & Bartlett through Learning, geologic time. LLC This secular science© Jones & Bartlett Learning, LLC changeNOT in Earth’s FOR systems SALE is ORanother DISTRIBUTION fundamental reason for NOT FOR SALE OR DISTRIBUTION studying Earth’s history. Slow, directional change means that Geology and the other Earth sciences are often termed a system can appear to exhibit no net change, like the envi- h historical sciences . What is meant by the term “his- ronments we observe on human time scales, when in fact torical science”? So far in this chapter, we have dealt with environments might be changing in a directional manner Earth systems as if they were components of a larger entity © Jones &on Bartlettgeologic scales Learning, of time. Furthermore,LLC what we observe© Jonesresembling & Bartlett a machine. Learning, The idea that LLC nature and its compo- NOT FORor SALE measure OR today DISTRIBUTION is by no means always representativeNOT nentsFOR can SALE be treated OR as DISTRIBUTION machines is not new. It dates at least of Earth’s distant past because conditions on Earth have to the time of Galileo (1564–1642) and René Descartes changed. Therefore, we cannot fully understand Earth’s (1596–1650; a French mathematician and philosopher for systems simply by looking at how they behave at present, whom the Cartesian coordinate system of geometry is because Earth’s systems have evolved. Indeed, Earth’s his- named). Even Hutton and other scientists of his time viewed tory has really consisted© ofJones a succession & Bartlett of vastly Learning, different LLCthe Earth as machine-like, in ©part Jones because & of Bartlett Sir Isaac New- Learning, LLC worlds leading up to ours.NOT FOR SALE OR DISTRIBUTIONton’s earlier formulation of theNOT law FORof gravitation SALE based OR onDISTRIBUTION Directional changes in Earth’s systems have resulted the behavior of the planets. from the flow of matter and energy between Earth’s systems With the doctrine that nature is a machine came another through geologic time. Among the numerous examples of view: that nature can be understood by taking it apart, like directionality in the history of Earth’s systems that we will a machine, into smaller parts that are more easily analyzed. consider© Jones are (1) the & formationBartlett of Learning, the solid Earth LLC by cooling This view has© Joneshad a tremendous & Bartlett impact Learning, on scientific LLC think- from NOTa molten FOR ball duringSALE the OR time DISTRIBUTION the solar system formed, ing and is NOTreferred FOR to as SALE reductionism OR DISTRIBUTION. For example, we (2) the formation and evolution of the continents by the broke the larger whole Earth system into four basic com- continued transfer of molten material and heat from within ponent systems: atmosphere, biosphere, hydrosphere, and Earth’s interior to the lithosphere, (3) the early evolution solid Earth. Admittedly, these are very large parts, each of of the atmosphere during the degassing of the primitive which is itself a system! But, by breaking a system (in this © Jones &Earth Bartlett by volcanoes, Learning, and (4) LLC the origin and evolution of© Jonescase, the& Bartlett whole Earth) Learning, down into LLCsmaller components, we NOT FORlife, SALE which OR led DISTRIBUTIONfirst to photosynthesis and the oxygena-NOT canFOR presumably SALE ORexamine DISTRIBUTION the structure and behavior of the tion of the atmosphere and then ultimately to the origin of smaller components and identify particular cause and effect more complex organisms. The biosphere eventually began relationships. Each component can in turn consist of smaller to be integrated with Earth’s other systems and acted as a compartments with their own systems and fluxes. However, geologic force to produce new cycles, such as the geologic as we have already seen, Earth’s systems are not isolated but cycle of carbon. © Jones & Bartlett Learning, LLCopen to each other, and we ©cannot Jones fully &understand Bartlett them Learning, LLC Despite the flow ofNOT matter FOR and SALEenergy through OR DISTRIBUTION natu- without understanding their interactions.NOT FOR SALE OR DISTRIBUTION ral systems, however, natural systems are often assumed by Much of science is also based on the assumption that earth scientists to exist in a state of equilibrium, oscillating each effect (observation, outcome) has a particular cause and about an “average” long-term condition. In the short term, that we can predict an effect given a particular cause; this the system might change, but in the long term its average view of science is called determinism . Many of the phenom- behavior© Jones presumably & Bartlett does not. ThisLearning, view of nature LLC is widely ena and processes© Jones studied & byBartlett scientists, Learning, including those LLC who acceptedNOT today, FOR by SALEwhich it ORis often DISTRIBUTION referred to as the state study EarthNOT systems, FOR occur SALE on sufficiently OR DISTRIBUTION short time scales of dynamic equilibrium. If the system is disturbed away that the processes and their effects can be observed or mea- from its so-called equilibrium state, it is assumed that it sured. Determinism is associated with the simplest notion will return to its original state, given enough time. In other of cause and effect, namely that an effect has a single cause, words, there is presumably no net change to the system like that observed in a laboratory setting, which, unlike nat- © Jones &because Bartlett not enough Learning, time has LLC passed to have allowed net© Jonesural systems, & Bartlett typically Learning, represent isolated LLC or closed systems NOT FORchange SALE to occur.OR DISTRIBUTION NOT inFOR which SALE all factors OR thought DISTRIBUTION to affect the laboratory system

16 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 16 07/11/16 10:44 am are held constant and the factor of interest is allowed to vary. Question The notion that the simplest explanation of a phenomenon about reality © Jones is& theBartlett one that Learning, is most likely LLC to be correct is called Ock-© Jones & Bartlett Learning, LLC ham’s Razor , or the Principle of Parsimony , after William NOT FOR SALE OR DISTRIBUTION NOT FORExamination SALE OR DISTRIBUTION of Ockham (ca. 1297–1347). This principle has become an of available integral part of the scientific method because it emphasizes data that one should seek simplicity in scientific explanation. Hypothesis Nevertheless, Earth’s phenomena—its processes and is falsified Formulation their outcomes—are not© Jonesstrictly deterministic & Bartlett because Learning, in LLCof hypothesis © Jones & DisagreementBartlett Learning, LLC natural settings the sameNOT effect FOR might SALEhave multiple OR DISTRIBUTIONor over- NOT FORbetween SALE expectation OR DISTRIBUTION lapping causes. On seasonal time scales, for example, atmo- and observation Conduct spheric carbon dioxide is regulated by seasonal changes in Making a OR sunlight and photosynthesis (Figure 1.4 b), but when taken prediction a test on the scale of many millions of years, continental weath- Agreement between expectation ering ©also Jones affects & atmospheric Bartlett Learning,carbon dioxide. LLC Another © Jones & Bartlett Learning,and observation LLC primeNOT example FOR of the SALE notion OR of multiple DISTRIBUTION causation is the NOT FOR SALE OR DISTRIBUTION mass extinction of Earth’s biota. Mass extinctions occurred Hypothesis remains valid a number of times during Earth’s history, but not all have resulted from meteor impacts. The exact cause of each epi- sode has varied, and in some cases there might have been Figure 1.16 The iterative process of the scientific method. © Jones &more Bartlett than one Learning, cause that overlapped LLC in time. The processes© Jones & Bartlett Learning, LLC NOT FORthat SALE occurred OR during DISTRIBUTION the ancient past have also undoubtedlyNOT FOR SALE OR DISTRIBUTION varied with historical circumstances, or contingency. Con- other words, scientists attempt to falsify everything they can, tingency means that historical circumstances influence the and whatever is left presumably explains the phenomenon outcome of one or more processes or events. In other words, of interest, at least for the time being. The development of processes and events in Earth’s history are conditional—or the modern scientific method as outlined so far is largely contingent—on what happened© Jones before. & Bartlett Historical Learning,processes LLCattributed by scientists to the© Jones20th century & Bartlett philosopher, Learning, LLC set the stage for, and canNOT even constrain,FOR SALE the future OR behaviorDISTRIBUTION Karl Popper. Popper first publishedNOT FOR his highly SALE influential OR DISTRIBUTION of Earth’s systems. For example, although the chemical reac- work The Logic of Scientific Discovery in 1934. Popper stated tions themselves involved in weathering have remained the that the best hypotheses are the ones that can be easily falsified same (based on the Principle of Uniformitarianism), their because then one knows for sure that the hypothesis is false rates have been affected by the kinds of rocks exposed at and can move on to other hypotheses. However, although Earth’s© surfaceJones (which & Bartlett in turn Learning,depends on processesLLC like the hypotheses© Jones that are & not Bartlett falsified gainLearning, support, theyLLC too plate NOTtectonics FOR and SALE mountain OR building), DISTRIBUTION the presence or might somedayNOT be FOR falsified SALE as new ORdata DISTRIBUTIONappears or new tests absence of land plants (the roots of which accelerate weath- develop, for example by new technologies. ering), and the concentration of atmospheric carbon dioxide, This approach to science is best exemplified by exper- which, as already discussed, also affects rates of weathering. imental sciences such as physics and chemistry. Experi- ments usually involve a laboratory system (or a field setting) © Jones & Bartlett Learning, LLC © Jonesin which & Bartlett all conditions Learning, are held LLC constant except one to NOT FOR SALE1.6 Method OR DISTRIBUTION and study of NOT determineFOR SALE the role OR of DISTRIBUTION that particular condition, known as a variable , in the system; this makes prediction much easier earth’s evolving systems because the system is essentially being treated as a closed Many students have been introduced to “the” scientific system, “cut out” from its surroundings and thus its inter- “method,” but the scientific method in earth sciences differs connections with other systems. Each experiment must be somewhat from that which© Jones is normally & Bartlett taught in Learning,the class- LLCaccompanied by what is called© aJones control , &which Bartlett is identical Learning, LLC room. Earth scientists, especiallyNOT FOR geologists SALE and OR paleontolo- DISTRIBUTIONto the other experimental setups,NOT except FOR thatSALE none OR of the DISTRIBUTION gists, tend to think in a way that differs from that of other conditions is varied. The control allows one to distinguish scientists, in what to some degree resembles that of histori- any other potential change that might have occurred while a ans. This is because they are historians. The scientific method particular variable was being manipulated during the exper- as it is used in historical sciences like geology is a recurring iment. Earth scientists can also use experiments to formulate theme© throughout Jones & this Bartlett book. Learning, LLC and test hypotheses© Jones about & Bartlett what happens Learning, in nature. LLC These The NOT scientific FOR method SALE is OR iterative, DISTRIBUTION meaning it might need experimentsNOT might FOR be done SALE in theOR laboratory DISTRIBUTION (for exam- to be repeated. This also means the method is self-correcting. ple, on the melting and crystallization of rocks) or in the In other words, the scientific method feeds back on itself in a field (such as experiments on rates of weathering under dif- kind of feedback loop that is supposed to keep the thinking ferent conditions). The results are then applied to under- reasonable and on the right track ( Figure 1.16). Through standing the Earth under more complex conditions. So far, © Jones &this Bartlett process of Learning, finding out whatLLC doesn’t work, we presum-© Jonesthis is & the Bartlett scientific Learning,method into whichLLC students have been NOT FORably SALE come ORto a DISTRIBUTIONbetter understanding of what does work. InNOT indoctrinated.FOR SALE OR DISTRIBUTION

1.6 Method and Study of Earth’s Evolving Systems 17

9781284457162_CH01_001_022.indd 17 07/11/16 10:44 am More often than not, however, geologists use data that to conventional wisdom, more likely to overlook important already exists in nature and that are the end products of phenomena or data bearing on the question of interest. This © Jones the& Bartlettnatural processes Learning, of open LLC systems with all their interac-© Jonesmethod & Bartlettof multiple Learning, working hypotheses LLC was proposed NOT FORtions, SALE feedbacks, OR DISTRIBUTION and contingencies. Geologists typically testNOT inFOR 1897 SALE by the ORAmerican DISTRIBUTION geologist T. C. Chamberlin. The hypotheses by first looking for rocks, sediments, or fossils of method of multiple working hypotheses is especially apro- the appropriate age—on land, in cores taken in the oceans, pos to earth sciences, in which multiple factors acting on or both—and make observations or measurements on the different scales of time can interact to produce a final effect variables of interest. Then, geologists use what some have (see the previous discussion on multiple causation). termed retrodiction or postdiction© Jones (to & distinguish Bartlett it Learning,from pre- LLCHowever, rather than each© Jones scientist &formulating Bartlett mulLearning,- LLC diction), meaning geologistsNOT must FOR frequently SALE reason OR backwardDISTRIBUTION tiple hypotheses, what typicallyNOT happens FOR isSALE that scientists OR DISTRIBUTION from geologic data such as rocks and fossils to infer the processes working on a particular research problem tend to form and the rates of those processes that produced what is being “social” groups that favor a particular hypothesis. Although observed or measured. This is why the Principle of Uniformi- this is perhaps undesirable and can seem odd, it is under- tarianism is so important, because without it we would not standably human. Each scientist has had different training be able© toJones justify such& Bartlett a procedure. Learning, LLC and different© experiencesJones & than Bartlett others, Learning,so it is not surprising LLC OnNOT the FORother hand,SALE it isOR not DISTRIBUTIONuncommon for the geologic that each oneNOT brings FOR different SALE viewpoints OR DISTRIBUTION to a problem and record to indicate unusual, perhaps even unique, conditions not different ways of thinking about it and attempting to solve it. observed by humans. For example, when iridium was found Those with similar viewpoints on a particular question tend to be associated with the end-Cretaceous extinctions, the to proceed by consensus, more or less mutual agreement. hypothesis appeared that all mass extinctions had been Very importantly, however, different parties or individuals © Jones &caused Bartlett by meteor Learning, impacts, LLCand there was an immediate© Jonesmight & strongly Bartlett disagree Learning, with the consensusLLC on a particular NOT FORsearch SALE for ORiridium DISTRIBUTION layers in end-Cretaceous sections asso-NOT question;FOR SALE “group OR think” DISTRIBUTION can therefore stifle independent ciated with other mass extinctions. When was the last time thought and scientific research. In fact we are far from know- you observed a meteor impact? ing everything there is to know about Earth and its history. Obviously, there is a greater amount of uncertainty If this were not true, we would not have the multiplicity of involved in testing most hypotheses in earth sciences hypotheses about certain events and processes on Earth! because earth scientists© are Jones less assured & Bartlett of the constancy Learning, of LLCFurthermore, as previously© Jones stated, &the Bartlett Principle Learning, of LLC conditions in the naturalNOT environment FOR SALE through OR time DISTRIBUTION than in Uniformitarianism itself underliesNOT allFOR of science. SALE The OR pro DISTRIBUTION- a laboratory. Earth scientists, especially geologists and pale- cess of scientific induction itself cannot be proven to be the ontologists, are thus forced to reconstruct past phenomena best scientific method. In the process of induction, prem- through postdiction. It is primarily for these reasons that his- ises established by observation, measurement, or calcula- torical sciences are often viewed as being less “scientific” and tion are used to infer the unknown of the past, present, and as being© Jonesderivative & sciences Bartlett based Learning, ultimately on LLC physics and future. This© problem Jones is& sometimes Bartlett referredLearning, to as Hume’sLLC chemistry.NOT Hutton FOR and, SALE especially, OR DISTRIBUTIONLyell felt this way: Hutton, problem, afterNOT the FOR Scottish SALE philosopher OR DISTRIBUTION who formulated perhaps because he was associated with the Enlightenment it, and has long plagued philosophers. Briefly stated, and Lyell because of his extreme form of uniformitarianism. Hume posed the question: how do we know induction is But the argument that experimental sciences are somehow the best method? To establish unequivocally that induc- superior to historical ones is flawed for several reasons. First, tion is the best method, we would have to use deduction. © Jones &any Bartlett experimental Learning, setting makes LLC certain assumptions, con-© JonesBut a &deductively Bartlett validLearning, argument LLC does not make conclu- NOT FORsciously SALE or OR subconsciously, DISTRIBUTION and the underlying assumptionsNOT sionsFOR that SALE go beyond OR DISTRIBUTIONthe premises because the conclusion can be so numerous that they cannot all possibly be taken states things we already know. Furthermore, the prem- into account. Assumptions underlying an experiment might ises of deductive arguments are typically based on certain be false and, if so, could alter the outcome of an experiment, assumptions. These assumptions include the principle of so the hypothesis is rejected when it is actually true, or vice the uniformity of nature! What, then, about the future, versa. Second, even if the© Jonesresults are & unambiguous Bartlett Learning, and the LLCwhich is unknown? How could© Joneswe use a &deductively Bartlett valid Learning, LLC hypothesis is rejected, NOTscientists FOR frequently SALE do OR not DISTRIBUTIONdiscard argument to infer that inductionNOT will FOR work SALE in the OR future DISTRIBUTION the hypothesis completely. They either modify it or test it in a laboratory setting, much less for an ancient historical under different conditions. So-called anomalous results or one? We are, Hume argued, reduced to using induction to phenomena (such as the iridium layer discovered near Gub- validate induction. We really have no other choice than to bio, Italy) can even lead to new discoveries undetectable on assume the uniformity of nature embodied in the Principle of human© Jonestime scales. & BartlettWhen iridium Learning, was not detectedLLC at all Uniformitarianism.© Jones According & Bartlett to the Learning, argument, induction LLC otherNOT extinction FOR boundaries, SALE OR scientists DISTRIBUTION did not abandon the has workedNOT in the FOR past, so SALE it will work OR inDISTRIBUTION the future because impact hypothesis; instead, they focused on the extinctions nature’s behavior is presumably uniform. Although many associated with iridium or searched for new sections that philosophers have attempted to subvert Hume’s problem might be more complete and contain iridium layers. by logical means (Popper’s method of falsification was just Ideally, scientists are supposed to formulate multi- one attempt), no one has ever satisfactorily demonstrated © Jones &ple Bartlett hypotheses Learning, to explain natural LLC phenomena. If scientists© Jonesanother & approachBartlett that Learning, thoroughly LLC replaces induction. But NOT FORfavor SALE a “pet” OR hypothesis DISTRIBUTION over another, they are, accordingNOT natureFOR SALEis not always OR DISTRIBUTION uniform. Iridium layers and mass

18 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 18 07/11/16 10:44 am extinctions are prime examples but, as we will see through- theory develops is when scientists formulate conceptual out this text, by no means the only ones! frameworks that produce hypotheses that can be tested. This © Jones & BartlettAs we will Learning, also see, although LLC induction seems to work© Joneskind of& theoryBartlett might Learning, originate as LLC“thought experiments” in NOT FORmost SALE of the OR time, DISTRIBUTION the “experts” have frequently been wrong.NOT aFOR scientist’s SALE mind OR when DISTRIBUTION they imagine, “What if . . .?” In either In other chapters, for example, we will examine how the case, the formulation of a theory represents a scientifically hypothesis of “continental drift” was formulated about 1915. valid approach. If a scientific relationship is called a theory, This hypothesis was constructed using an inductive argu- there must be a reason. Thus, you must be wary when you ment, the premises of which were the “jigsaw” fit of the con- hear phrases like “it’s only a theory,” or “it’s just theoretical.” tinents and matching rocks© Jones and fossils & Bartlett on continents Learning, now LLCWhat are the data for the theory?© Jones Have hypotheses & Bartlett stemming Learning, LLC located on opposite sidesNOT of the FOR Atlantic SALE Ocean. OR From DISTRIBUTION these from the theory been tested andNOT corroborated? FOR SALE OR DISTRIBUTION premises, it was concluded by Alfred Wegener that the conti- More much certain relationships between phenomena, nents must have originally been joined together into a larger which are considered fundamental truths, are called laws. supercontinent named Pangaea (“all land”; Figure 1.17). It Laws are embedded within a larger body of theory. Laws note was this hypothesis that would ultimately lead to the theory strikethrough are frequently “empirical” or derived from of plate© Jonestectonics. & However, Bartlett in Learning,1915 there was LLC no known observation© and Jones experiment. & Bartlett Such laws Learning, attempt to LLCexplain force NOT(which FORwe now SALE know toOR be relatedDISTRIBUTION to convection cells repeated observationsNOT FOR without SALE really OR understanding DISTRIBUTION why the and seafloor spreading) that moved the continents. As a phenomena occur. Sir Isaac Newton’s laws of motion, which result, almost all other scientists rejected the hypothesis. Not can be used to predict eclipses and planetary movements until the second half of the 20th century did scientists begin both in the future and the past, are examples of such laws to obtain data that indicated the existence of convection cells (but in Newton’s time, like Wegener centuries later, some © Jones &deep Bartlett within the Learning, Earth and their LLC role in driving plate tecton-© Jonesscientists & Bartlett could not Learning, understand howLLC a force called grav- NOT FORics SALE and the OR movement DISTRIBUTION of the continents. NOT ityFOR could SALE act across OR the DISTRIBUTION great distances separating planets). Then, the hypothesis began to be regarded as part of a Partly because of the power of these laws, Newton is often larger theory now called plate tectonics. The value of a the- considered the quintessential scientist of all time. For a rela- ory, like the theory of plate tectonics, is that it takes obser- tionship to be a law, it must be repeatable and hold under vations and data and synthesizes them into a larger, more a variety of conditions. Newton’s laws of motion hold, for coherent explanatory picture.© Jones Hutton’s & Bartlett Theory of Learning,the Earth LLCexample, in other solar systems;© Jones otherwise, & theyBartlett would Learning,not LLC (see the section “SourcesNOT and FORFurther SALE Reading”) OR and DISTRIBUTION Lyell’s be laws. But laws are abstractions.NOT TheyFOR help SALE explain OR what DISTRIBUTION Principles of Geology are examples of geologic theory. The has happened or will happen, irrespective of other factors prime value of a theory is that it suggests further hypoth- such as contingency or historical circumstances, but they do eses and tests to substantiate or refute the theory; thus, a not tell us exactly what happened. theory might be modified, as was Lyell’s original view of uni- Earth scientists deal with history, which is about chang- formitarianism,© Jones or & even Bartlett overturned. Learning, Another wayLLC in which ing conditions© Jones through &time. Bartlett Historical Learning, conditions are LLC never NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Africa India

Cynognathus Mesosaurus Lystrosaurus Glossopteris

Data from: Colbert, C. H. 1973. Wandering Lands and Animals. London: Hutchinson & Company.

© Jones Figure& Bartlett 1.17 TheLearning, hypothesis of LLC continental drift was asedb on the© “jigsaw” Jones fit of& the Bartlett continents Learning, and matching rocksLLC and fossils on NOT FORcontinents SALE nowOR located DISTRIBUTION on opposite sides of the Atlantic Ocean. NOT FOR SALE OR DISTRIBUTION

1.6 Method and Study of Earth’s Evolving Systems 19

9781284457162_CH01_001_022.indd 19 07/11/16 10:44 am exactly the same because of contingency. So, instead of laws, things: phenomena that require explanation (i.e., a “good” earth scientists tend to rely on theory, usually backed up by research question or problem) and ways to test hypotheses © Jones observation& Bartlett and Learning, measurement, LLC and, to a lesser extent, exper-© Jonesor explain & Bartlett phenomena. Learning, As you proceed LLC through the text, NOT FORiment. SALE Instead OR of DISTRIBUTION laws, general truths in geology are usuallyNOT youFOR should SALE be awareOR DISTRIBUTION of how hypotheses or theories have referred to as principles. A principle is like a good “rule been arrived at and tested in earth sciences. of thumb” because it might have some exceptions, whereas laws are supposed to be invariable. The Principles of Super- position and Uniformitarianism are examples. Superposition typically holds unless, ©for Jones example, & rocks Bartlett have been Learning, over- LLC Concept and Reasoning© Jones & Che Bartlettck Learning, LLC turned by mountain building,NOT FOR resulting SALE in their OR order DISTRIBUTION from NOT FOR SALE OR DISTRIBUTION top to bottom being reversed. 1. How does the science of geology resemble or differ Despite this outline of basic method, most scientists from other sciences with regard to processes and their don’t go around thinking continuously about using the sci- rates, experimental versus natural conditions, causation, entific method; their thinking is typically much, much looser contingency, and laws? than that.© Jones Instead, & scientists Bartlett tend Learning, to look primarily LLC for two © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

© Jones & BartlettSummary Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION nn Earth’s climate has influenced human civilization unique (or nearly so) conjunction of circumstances, for thousands of years and will continue to do so in making the systems essentially irreversible and giving the future. During the 20th century, the expanding them a history. human population, agriculture, and industrialization nn Earth’s systems interact with one another through pos- all began to significantly© Jones affect & BartlettEarth’s environments. Learning, LLCitive and negative feedback© Jonesto maintain & Bartlett a relatively Learning, LLC The view amongNOT scientists FOR that SALE human ORactivities DISTRIBUTION are constant environment. PositiveNOT feedback FOR SALE promotes OR an DISTRIBUTION dramatically influencing Earth’s climate and biota led effect, whereas negative feedback counters an effect. to the science of Earth systems. nn Earth scientists use the same basic approach as other nn A system is a series of parts or compartments that scientists in seeking cause and effect relationships: the comprise a larger integrated whole. The major Earth Principle of Uniformitarianism. ©systems Jones are &the Bartlett solid Earth, Learning, atmosphere, LLChydrosphere, nn Many Earth© Jones processes & have Bartlett largely Learning,remained the sameLLC NOTand biosphere. FOR SALE Each system OR DISTRIBUTION is an open system charac- throughNOT time, FORacting SALEimperceptibly, OR DISTRIBUTION whereas other terized by the cyclic flow of matter and energy. processes have acted suddenly and catastrophically, nn Earth’s systems share a number of features: The systems such as extraterrestrial impacts. In fact, there has been maintain themselves far from equilibrium by exchang- plenty of time for both slow processes and unusual ing matter and energy with their environment, which ones to have caused enormous change on Earth. © Jones & Bartlettincludes Learning,other systems andLLC their products. The systems© Jonesnn Earth & Bartletthas not existed Learning, strictly in LLC an equilibrium state NOT FOR SALEinteract OR with DISTRIBUTION one another and might do so nonlinearly.NOT FORof no SALE net change OR through DISTRIBUTION time. It has evolved, and its Because of the flow of matter and energy through the history exhibits secular change, or directionality. systems and the interactions of the systems with one nn Given the variety of processes that occur over long another, the complexity of each system—or the num- spans of time, geologists and other earth scientists ber of its components—increases. Each system is typically cannot reduce the scientific study of Earth’s typically hierarchical,© Jones with different & Bartlett processes Learning, acting LLCsystems to simple cause and© Jones effect relationships & Bartlett like Learning, LLC and interacting onNOT different FOR time SALE scales. AOR sixth DISTRIBUTION trait of those observed in controlledNOT FORlaboratory SALE settings. OR DISTRIBUTION Earth’s evolving systems is that the direction and mag- We really cannot understand all processes of Earth or nitude of change is affected by preexisting conditions, humankind’s rapid impact on Earth’s environments or contingency. The geologic record strongly indicates without understanding Earth’s geologic record and that much of what has occurred on this planet often processes, which occur on different scales of time. ©depended Jones on& Bartlettcontingency Learning, and was the LLC result of a © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

20 Chapter 1 Introduction: Investigating Earth’s Systems

9781284457162_CH01_001_022.indd 20 07/11/16 10:44 am Key Terms © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALEabsolute OR age DISTRIBUTION NOT methodFOR SALEof multiple OR working DISTRIBUTION hypotheses actualism multiple causation anthropogenic Ockham’s Razor biosphere open system catastrophism © Jones & Bartlett Learning, LLCPangaea © Jones & Bartlett Learning, LLC contingency NOT FOR SALE OR DISTRIBUTIONplate tectonics NOT FOR SALE OR DISTRIBUTION convection cells Principle of Faunal Succession cryosphere Principle of Parsimony determinism Principle of Superposition directionality© Jones (secular & Bartlett change) Learning, LLC Principle of Uniformitarianism© Jones & Bartlett Learning, LLC dynamicNOT equilibrium FOR SALE OR DISTRIBUTION radioactive decayNOT FOR SALE OR DISTRIBUTION feedback reductionism flux relative age geologic time reservoirs © Jones & Bartlettgreenhouse gasesLearning, LLC © Jonessteady & state Bartlett Learning, LLC NOT FOR SALEhistorical OR science DISTRIBUTION NOT stratifiedFOR SALE OR DISTRIBUTION homeostasis system hydrosphere

Review© Jones Questions& Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 1. What are the four basic Earth systems? 8. Give examples of how life has acted as a geologic 2. What are the basic characteristics of a natural system? force. 3. Diagram the flow of matter and energy that occurs 9. What is meant by the term “geologic time”? in the atmosphere, lithosphere, biosphere, and 10. Why is the Principle of Uniformitarianism important © Jones & Bartletthydrosphere. Learning, LLC © Jonesto & the Bartlett study of Earth’sLearning, systems? LLC 4. What is the difference between true equilibrium and 11. How does the modern view of uniformitarianism dif- NOT FOR SALEsteady OR state? DISTRIBUTION Is steady state a kind of equilibrium?NOT FORfer SALEfrom that OR of L yell’s?DISTRIBUTION Explain. 12. What is the importance of the following to the 5. How do each of Earth’s systems interact to control history of Earth’s systems: (a) contingency and atmospheric carbon dioxide on geologic scales of time? (b) directionality. 6. How does the biosphere© Jones regulate & Bartlett atmospheric Learning, car- LLC13. What are some key reasons© Jonesfor studying & Bartlett the history Learning, LLC bon dioxide on different scales of time? of Earth? 7. Describe positiveNOT and negative FOR SALEfeedback. OR Give DISTRIBUTION exam- 14. How are geologists both scientistsNOT FOR and historians?SALE OR DISTRIBUTION ples using Earth’s systems.

1.6 Method and Study of Earth’s Evolving Systems 21

9781284457162_CH01_001_022.indd 21 07/11/16 10:44 am Food for Thought: © Jones & FurtherBartlett ActivitiesLearning, In LLC and Outside of Class© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 1. Do you think the Earth is in equilibrium? Why or decrease atmospheric carbon dioxide in coming why not? On what time scales might it appear to be decades that would keep atmospheric carbon diox- in equilibrium? ide at relatively constant levels? 2. Why do you © supposeJones &the Bartlett measurements Learning, of LLC5. Distinguish between the different© Jones meanings & Bartlett that have Learning, LLC Figure 1.4b were taken in Hawaii? been given to the term “uniformitarianism.” NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 3. As described in the text, the impact of anthropo- 6. What is a control, and why is it important to a labo- genic activities on Earth greatly accelerated during ratory experiment? How could “natural” conditions the 20th century. Based on absolute ages, Earth is recorded in rocks and sediments serve as controls? about 5 billion years old. To get some idea of how 7. James Hutton likened the Earth to a machine, ©fast Jones anthropogenic & Bartlett impacts Learning, have occurred, LLC calculate whereas© some Jones later &workers Bartlett have likenedLearning, it to a giantLLC the percentage of Earth’s existence represented by the organism. Is one of these descriptions better than the NOT20th FORcentury. SALE OR DISTRIBUTION other? NOTWhy? FOR SALE OR DISTRIBUTION 4. Assume that anthropogenic carbon dioxide emis- 8. Distinguish between laws as they are used in exper- sions actually cause global warming. Are there any imental sciences and the use of principles like those plausible negative feedback mechanisms that would used in geology. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Sources and© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Further ReadingNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Ager, D. 1993. The new catastrophism: The importance of Lovelock, J. 1988. The ages of Gaia: A biography of our liv- the rare event in geological history. Cambridge, UK: ing Earth. New York: W. W. Norton. Cambridge University Press. Mackenzie, F. T., and Lerman, A. 2006. Carbon in the geo- Chaisson,© Jones E. J. & 2001. Bartlett Cosmic Learning, evolution: The LLC rise of com- biosphere:© JonesEarth’s outer & Bartlett shell. Dordrect, Learning, The Nether LLC- NOTplexity FOR in nature SALE. Cambridge, OR DISTRIBUTION MA: Harvard University lands: NOTSpringer. FOR SALE OR DISTRIBUTION Press. Martin, R. E. 1998. One long experiment: Scale and pro- Chamberlin, T. C. 1897. The method of multiple working cess in Earth history. New York: Columbia University hypotheses. Journal of Geology, 5, 837–848. Press. © Jones & BartlettCollier, M., Learning, and Webb, R. LLC H. 2002. Floods, droughts, and© JonesPeters, & E. Bartlett K. 1996. Learning, No stone unturned: LLC Reasoning about climate change. Tucson, AZ: University of Arizona rocks and fossils. New York: W. H. Freeman. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Press. Pielou, E. C. 2001. The energy of nature. Chicago: Univer- Coveney, P., and Highfield, R. 1991. The arrow of time: A sity of Chicago Press. voyage through science to solve time’s greatest mystery. Schumm, S. A. 1991. To interpret the Earth: Ten ways to be New York: Fawcett Columbine. wrong. Cambridge, UK: Cambridge University Press. Dott, R. H. 1998. What© Jones is unique & aboutBartlett geological Learning, rea- LLCSimpson, G. G. 1963. Historical© Jones science. In& C.Bartlett C. Albrit -Learning, LLC soning? GSA TodayNOT (October), FOR SALE1. OR DISTRIBUTIONton (Ed.), The fabric of geologyNOT (pp. FOR 24–48). SALE Reading, OR DISTRIBUTION Frodeman, R. (1995) Geological reasoning: geology as an MA: Addison-Wesley. interpretive and historical science. Geol Soc Am Bull, von Bertalanffy, L. 1968. General system theory. New York 107:960–968. George Braziller. Gorst, M. 2001. Measuring eternity: The search for the Westbroek, P. 1991. Life as a geological force. New York: © beginningJones of& time Bartlett. New York: Learning, Broadway LLCBooks. W. W. ©Norton. Jones & Bartlett Learning, LLC Hutton,NOT J.FOR 1795. SALE Theory of OR the Earth.DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

22 Chapter 1 Introduction: Investigating Earth’s Systems

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